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Subvert cognition! Bacteria and archaea also have an innate immune system! The latest Science research by Zhang Feng's team reveals the specific mechanism of prokaryotic innate immunity!
In nature, viruses and bacteria are ubiquitou.
It is worth noting that bacteria are not always invaders, they also face attack from bacteriophage.
In addition to this, have bacteria also evolved defense mechanisms similar to the innate immune system of eukaryotes?
On August 12, 2022, Professor Zhang Feng's team published a research paper in Science entitled: Prokaryotic innate immunity through pattern recognition of conserved viral protein.
The study shows that an innate immune system similar to eukaryotic NLRs is also prevalent in bacteria and archaea (collectively referred to as prokaryotes), and that these NLR-like genes share four families and are specific for two highly conserved phage proteins sex senso.
The study found that bacteria and archaea are able to quell the spread of viruses in microbial communities by directly detecting key proteins of invading viruses and causing "suicide.
Prof Feng Zhang, this work shows how pattern recognition can be remarkably unified in very different organisms, integrating genetics, bioinformatics, biochemistry and structural biology methods into one study to understand this fascinating The molecular system is very excitin.
Prior to this, Feng Zhang's team had discovered a group of bacterial and archaeal STAND nucleoside triphosphatases (NTPases), called Avs (antiviral STAND.
However, the mechanism by which Avs proteins protect bacteria from attack by tailed phages remains unclea.
Prokaryotes have innate immune systems similar to eukaryotic NLRs
Through genetic screening in .
The research team found that co-expression of the Avs protein and its cognate target protein in .
Avs proteins recognize hallmark viral proteins of bacteriophages
Then, Zhang Feng's team reconstituted the Avs activity in vitro, focusing on the Avs activity of Salmonella (SeAvs3) and Escherichia coli (EcAvs4), both of which contain the N-terminal PD-DExK nuclease effecto.
SeAvs3 and EcAvs4 are phage-activated double-stranded endonucleases
Not only that, the research team also determined the cryo-electron microscopy structures of the SeAvs3-terminase and EcAvs4-portal complexes, revealing that both form tetramers and that binding is mediated by a shape-complementary extended interface, where each Avs subunit The C-terminal sensor domain of the base binds a single target protei.
Cryo-electron microscopy structures of the SeAvs3-terminase and EcAvs4-portal complexes
Finally, bioinformatic analysis of Avs proteins revealed that at least 18 different N-terminal effectors are modularly exchanged between Avs homologous genes, and that Avs genes are widely distributed in various phyla of bacteria and archaea, which is likely to be widespread caused by horizontal gene transfe.
Avs genes are widely distributed in prokaryotes
More interestingly, the research team also found that bacteriophages also "retaliate" - by encoding and expressing the inhibitory protein of Avs, highlighting the extensive arms race between prokaryotes and viruses, which can be described as "one foot high, magic" One zhang tal.
Phages encode and express Avs inhibitory proteins against the innate immune system of prokaryotes
Overall, this Science study shows that the Avs family of defense proteins against phages similar to the eukaryotic NLRs are also present in bacteria and archae.
The defense mechanisms of Avs proteins underscore the similarities of prokaryotic and eukaryotic defense strategies and extend the immune pattern recognition mechanisms of pathogen-specific proteins to all three domains of life (bacteria, archaea, eukaryotes), providing Basic research on innate immunity opens new door.
Original source:
LINYI ALEX GAO, et a.
Prokaryotic innate immunity through pattern recognition of conserved viral protein.
SCIENCE, 12 Aug 2022, Vol 377, Issue 660